乙烯是果实成熟的启动因素，但有时也能抑制成熟。
参考答案：错
三联体油雾器的油质要（），油量为存油杯容积的（）。
_____ China’s reform and opening up in late 1978, its quick development has aroused worldwide attention, which has made America anxious about it.
A．When
B．As
C．While
D．Since
